Alderson Phil, Campbell Gillian, Smith Andrew F, Warttig Sheryl, Nicholson Amanda, Lewis Sharon R
National Institute for Health and Care Excellence, Level 1A, City Tower,, Piccadilly Plaza, Manchester, UK, M1 4BD.
Cochrane Database Syst Rev. 2014 Jun 4;2014(6):CD009908. doi: 10.1002/14651858.CD009908.pub2.
Inadvertent perioperative hypothermia occurs because of interference with normal temperature regulation by anaesthetic drugs and exposure of skin for prolonged periods. A number of different interventions have been proposed to maintain body temperature by reducing heat loss. Thermal insulation, such as extra layers of insulating material or reflective blankets, should reduce heat loss through convection and radiation and potentially help avoid hypothermia.
To assess the effects of pre- or intraoperative thermal insulation, or both, in preventing perioperative hypothermia and its complications during surgery in adults.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 2), MEDLINE, OvidSP (1956 to 4 February 2014), EMBASE, OvidSP (1982 to 4 February 2014), ISI Web of Science (1950 to 4 February 2014), and CINAHL, EBSCOhost (1980 to 4 February 2014), and reference lists of articles. We also searched Current Controlled Trials and ClinicalTrials.gov.
Randomized controlled trials of thermal insulation compared to standard care or other interventions aiming to maintain normothermia.
Two authors extracted data and assessed risk of bias for each included study, with a third author checking details. We contacted some authors to ask for additional details. We only collected adverse events if reported in the trials.
We included 22 trials, with 16 trials providing data for some analyses. The trials varied widely in the type of patients and operations, the timing and measurement of temperature, and particularly in the types of co-interventions used. The risk of bias was largely unclear, but with a high risk of performance bias in most studies and a low risk of attrition bias. The largest comparison of extra insulation versus standard care had five trials with 353 patients at the end of surgery and showed a weighted mean difference (WMD) of 0.12 ºC (95% CI -0.07 to 0.31; low quality evidence). Comparing extra insulation with forced air warming at the end of surgery gave a WMD of -0.67 ºC (95% CI -0.95 to -0.39; very low quality evidence) indicating a higher temperature with forced air warming. Major cardiovascular outcomes were not reported and so were not analysed. There were no clear effects on bleeding, shivering or length of stay in post-anaesthetic care for either comparison. No other adverse effects were reported.
AUTHORS' CONCLUSIONS: There is no clear benefit of extra thermal insulation compared with standard care. Forced air warming does seem to maintain core temperature better than extra thermal insulation, by between 0.5 ºC and 1 ºC, but the clinical importance of this difference is unclear.
围手术期意外低温是由于麻醉药物干扰正常体温调节以及皮肤长时间暴露所致。已提出多种不同的干预措施来通过减少热量散失维持体温。保温措施，如额外增加隔热材料层或使用反射毯，应能减少通过对流和辐射的热量散失，并有可能有助于避免体温过低。
评估术前或术中保温措施或两者联合应用对预防成人手术期间围手术期低温及其并发症的效果。
我们检索了考克兰对照试验中央注册库（CENTRAL）（《考克兰图书馆》2014年第2期）、医学期刊数据库（MEDLINE）、OvidSP（1956年至2014年2月4日）、EMBASE、OvidSP（1982年至2014年2月4日）、科学引文索引（ISI Web of Science）（1950年至2014年2月4日）以及护理学与健康领域数据库（CINAHL）、EBSCOhost（1980年至2014年2月4日），并查阅了文章的参考文献列表。我们还检索了当前对照试验库和美国国立医学图书馆临床试验注册库（ClinicalTrials.gov）。
与标准护理或其他旨在维持正常体温的干预措施相比，保温措施的随机对照试验。
两位作者提取数据并评估每项纳入研究的偏倚风险，第三位作者核对细节。我们联系了一些作者以获取更多细节。我们仅收集试验中报告的不良事件。
我们纳入了22项试验，其中16项试验提供了部分分析数据。这些试验在患者类型和手术、体温测量的时间以及特别是所采用的联合干预措施类型方面差异很大。偏倚风险大多不明确，但大多数研究中实施偏倚风险高，失访偏倚风险低。额外保温与标准护理的最大对比研究有5项试验，共353例患者，手术结束时加权均数差（WMD）为0.12℃（95%置信区间 -0.07至0.31；低质量证据）。手术结束时将额外保温与强制空气加温进行比较，WMD为 -0.67℃（95%置信区间 -0.95至 -0.39；极低质量证据），表明强制空气加温时体温较高。未报告主要心血管结局，因此未进行分析。两种比较在出血、寒战或麻醉后护理期间的住院时间方面均未显示出明显影响。未报告其他不良反应。
与标准护理相比，额外保温没有明显益处。强制空气加温似乎比额外保温能更好地维持核心体温，高出0.5℃至1℃，但这种差异的临床重要性尚不清楚。
